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39 Cards in this Set

(T/F) A catalyst acts by increasing the rate of the forward reaction more than the reverse reaction.

False; Lowering of activation energy must be by the same numerical value in either direction (forward to reverse rate; ie. equilibrium constant) unchanged.

(T/F) A catalyst may have molecular weight as low as 1 or higher than 200,000.

True; Acid-catalyzed reactions are enhanced by the presence of protons, H+, which have a 'molecular' weight of 1, while enzymes, which catalyzez many biochemical reactions, are usually proteins of higher molecular weight, often in exces of 200,000.

What is Hess's law?

The total change in a thermodynamic state function (such as enthalpy here) can be found as the sum of the changes for a series of steps with the same net result.

What is heat of fusion, delta(H_f)?

delta(H_f) is defined as the enthalpy change accompanying the reaction, real or hypothetical of elements in their standard states coming together to form the product in question.

What would you expect the energy of the formation of gaseous water from a liquid compared to the formation of liquid water?

The formation of gaseous will be less exothermic than the formation of liquid water.

Formation of water can be thought of as what?

Combustion since H2 is reacting with O2 and therefore its exothermic.

Cation radius is better/smaller than a neutral atom?

Smaller b/c the removal of electrons decreases the electrostatic repulsion between remaining electrons, thereby allowing the nucleus to pull them closer, decreasing the ionic radius.

Anion radius is bigger/smaller than a neutral atom?

Bigger b/c of an increased number of electrons that repel one another.

Pauli exclusion principle

No two electrons on a single atom can have an identical set of
values for the four quantum numbers n, l, m_l, and m_s.

Heisenberg uncertainty principle

One cannot simultaneously determine the momentum and the location of an electron precisely.

the low ionization energy of metals allows them to easily give up an electron to a willing acceptor; metals are therefore easily oxidized and thus make good reducing agents.

What is dalton's law of partial pressures state?

The pressure exerted by an ideal gas in a mixture is the same as it would be if the gas were to occupy the same volume alone.

A 200mnL flask contains oxygen at 200mmHg and a 300mL flask contains neon at 100mmHg. The two flasks are then connected so that each gas fills their combined volumes. Assuming no change in temperature, what is the partial pressure of neon in the final mixture?

Dalton's law of partial pressures states that the pressure exerted by an ideal gas in a mixture is the same as it would be if the gas were to occupy the same volume alone. If we focus on the neon we can approach this problem as if the volume increases from the initial 300 mL to the combined 500 mL and use the relationship P1V1 = P2V2 (Boyle's law). Note that, qualitatively, an increase in volume will lead to a decrease in pressure and so the answer must be less than 100 mmHg. Completing the calculations: P2 = P1V1/V2 = (100 mmHg)(300 mL)/(500 mL) = 3/5(100 mmHg) = 60 mmHg.

In which of the following does inelastic collisions occur between molcules:
a. real gases
b. ideal gases
c. fusion reactions

Inelastic collisions do occur in real gases and a nuclear fusion reaction is a reaction in which two nuclei collide to form a new, heavier nucleus.
Ideal gasses are elastic.

Which are the assumpions of the Kinetic Theory of Gases?

an ideal gas is composed of particles of:
negligible volume in constant but random motion,
that there are no interactions among these particles,
that any collisions are completely elastic, and that
the average kinetic energy of the particles is proportional to the absolute temperature.

What hybridization does the central atom of the ion AB_6^-3 have (its octahedral geometry)?

The hybridization of the central atom in a molecule or ion is easily determined by counting the number of bonds and electron pairs of the central atom and then counting orbitals, in s-p-d-f order. sp^3d^2.

When would you see a sp^2d hybridization?

sp^2d, is a much less common hybridization. It is found in molecules and ions such as ClO2-, where the central chlorine atom has two lone pairs and is bonded to the two oxygen atoms. This ion also has a dbl(?) bond which is formed via the side-by-side overlap of the third chlorine p orbital with one of the oxygen p orbitals. Since this chlorine p orbital is already in use, it is necessary for one of the chlorine 3d orbitals to participate in the hybridization.

(T/F) Transition elements reside in the center, or d-block, of the Periodic Table and are often called transition metals because of their metallic character.

True.

(T/F) Most transition elements have incomplete d subshells, while the next s sublevel is occupied.

True; for example, vanadium has the electron configuration V = [Ar]4s^2 3d^3 ; its 4s sublevel is occupied while its 3d subshell is incomplete.

(T/F) Most transition elements have multiple oxidation states.

True; for example, vanadium for example can lose the 4s electrons, the 3d electrons, or both to form a 2+, 3+ or 5+ cation respectively.

(T/F) Transition metals include heavy metals.

True; heavy metals such as gold and mercury are among their ranks.

(T/F) Transition metals are located in each period of the periodic table.

False; they are not found in the first two rows of the Periodic Table.

Where are inert gases located on the periodic table?

Inert gases, are the elements found in the last column of the table. aka. noble gases

What are the characteristics of inert gases?

Based on their position, one can predict that these elements will generally have:
* the smallest atomic radii
* the largest ionization energy
of the elements within a given period, or row, of the Periodic Table.

Where are active metals found on periodic table and what are their characteristics?

- elements found on the far left side of the table, particularly those in the lower left-hand corner
- These elements are relatively large in size, and have low ionization energies, electron affinities, and electronegativities.
- aptly named; they are so reactive that they are found in nature only in cationic form.

Where are active non-metals found on periodic table and what are their characteristics?

- active non-metals are found in the upper right-hand corner of the Periodic Table (but not in the last column)
- generally have large electron affinities and electronegativities.

(T/F) Transition elements may have smaller atomic radii because electrons are added to the d orbitals of a lower principal quantum number.

True.

2 X(g) + Y(g) ==> Z(g)

If stoichiometric quantities of X(g) and Y(g) are introduced into a sealed, rigid container at constant temperature with an initial pressure of 12 atmospheres, what will the pressure in the container be when the reaction is complete?

4 atmospheres; PV=nRT see that pressure is prop to moles.

2 X(g) + Y(g) ==> Z(g)

If stoichiometric quantities of X(g) and Y(g) are placed in a sealed, flexible container with an initial volume volume of 30 liters at STP, what volume of Z(g) will be produced?

10 liters; PV=nRT see that volume is prop to moles.

What does a flexible container signify?

pressure is constant.

What does a rigid container signify?

Pressure will change.

How would you go about solving the following problem: What is the empirical formula of a compound which on analysis is shown to consist of 12.5% hydrogen, 37.5% carbon, and 50% oxygen by mass?

Assume 100g sample and divide each by its atomic mass.

(T/F) Group IA active metals can form only cations with a +1 oxdation # when reacted w/ halogens, alcohols or water.

True.
Group IA active metals react with elemental oxygen, for example to form oxides of the general formula M2O, and these oxides can then react with water to form hydroxides of the general formula MOH.